广西合山石村矿超高有机硫煤饱和烃特征分析

Saturated hydrocarbon characteristics of superhigh-organic-sulfur coals in Heshan Shicun mine, Guangxi

以合山石村矿超高有机硫煤为研究对象,利用带能谱的扫描电镜(SEM-EDX)及气相色谱(GC)和色谱-质谱联用(GC-MS)分析技术,综合分析探讨了研究区样品中有机质来源、沉积环境及物源输入。结果表明,研究区样品镜质体反射率均值1.76%,全硫含量均值6.01%,其中有机硫含量占比达94.3%,为高成熟度的超高有机硫煤。饱和烃色谱图中未分辨的复杂混合物(UCM)鼓包明显,前峰及双峰型均有分布,前峰型主峰碳为C16、C18、C21,双峰型主峰碳为C18、C27,化合物降姥鲛烷、脱氢松香烷、咔达烯均有发现,规则甾烷C27、C28、C29均呈"V"型分布,说明沉积母质受藻类等低等水生生物与高等植物双重输入的影响。姥植比参数、C31-35藿烷呈阶梯式递减的分布特征表明在海相碳酸盐台地成煤带中存在一定的氧化条件。扫描电镜中拍摄到的铁含氧硫酸盐、细胞充填环状黄铁矿说明在沉积质晚期成岩阶段受到一定程度热液作用影响。

A superhigh-organic-sulfur(SHOS) coals were chosen to study the environmental causes of Heshan coal origin. Based on routine analysis such as scanning electron microscope(SEM-EDX) observation, gas chromatograph(GC) and gas chromatograph-mass spectrometry(GC-MS), the composition and molecular geochemical features of organic matter were analyzed to deeply reveal the organic matter sources, sedimentary environments and provenance inputs. The results indicate that the average vitrinite reflectance of the samples is 1.76%, and the average total sulfur is 6.01%, among which the organic sulfur content accounts for 94.3%, belonging to a high-maturation super high organic sulfur coal. Unresolved Complex Mixtures(UCM) bulge is obvious in the saturated hydrocarbon chromatogram, both front and bimodal peaks are found. The main carbon peaks of the front peak type are C16, C18, C21 and the bimodal is C18 and C27. Meanwhile, these compounds norpristane, dehydroabietane, cadalene have been found in samples, and regular sterane C27, C28, C29 show a "V" type distribution, which indicates that sedimentary parent material is affected by the double input of lower aquatic organisms and high plants. The distribution of hopane in C31-35 decreases stepwise, and the ratio of pristane to phytane shows that there are certain oxidation conditions in the coal-forming zone of marine carbonate platform. Fe(Si, Al)-oxysulfate and cell-filled pyrite observed by SEM indicate that the sedimentary diagenesis is affected by hydrothermal process to some extent in the diagenetic stage of late sedimentary facies.